快堆浸入式事故余热排出系统程序开发

针对示范快堆的设计需要,在法国快堆系统程序OASIS的基础上,引入热分层与盒间流模型,开发了浸入式事故余热排出系统分析程序。利用该程序对CEFR的非能动事故余热排出系统进行了整体建模,分析了稳态和全厂断电工况下的性能,并利用其他系统程序的结果进行了验证。结果表明:该程序能较好地反映事故余热排出系统的瞬态变化过程。     

CP300机组启停堆期间反应性风险分析

在启停堆期间,由于堆芯释放的能量较少,若发生故障,通常有充分的时间来防止或缓解事故的发生,所以停堆期间的反应性安全通常得不到应有的重视。但在停堆时并非所有的安全系统均可使用;停堆时多半是手动操作,反应堆风险更多的转嫁到操纵人员身上,加之启停堆期需要配合做许多物理实验,需要特别注意可能会向堆芯引入反应性的操作和事故,需要对启停堆期间的安全风险有足够的认识。本文通过对启停堆期间反应性变化分析,着重讨论可能会发生威胁反应堆安全的事故,以提高操纵员对启停堆期间的反应性事件缓解和控制。     

池式钠冷快堆交互式安全分析软件开发

为建立适用于池式钠冷快堆的仿真机,开发了基于法国快堆系统分析程序OASIS的交互式安全分析系统,实现了实时绘图、动态显示等可视化功能。利用该系统模拟了中国实验快堆的堆芯、主热传输系统、事故余热排出系统,以及控制调节系统和保护系统,分析了各个功率台阶的稳态及满功率下流量阶跃瞬态工况。分析结果与设计值符合度良好,表明该系统具有良好的适用性,可用于人员培训与安全审评等。     

高温气冷堆核电厂主控室可居留系统的优化

依据高温气冷堆固有安全性和非能动的安全系统、无堆芯熔化事故的工况,分析了设计基准事故条件下高温气冷堆主控制室可居留系统的特点,提出了高温气冷堆主控制室可居留系统的优化建议。     

AP1000功率量程中子注量率正变化率高紧急停堆定值和时间常数研究

核仪表系统(RPN)是核电厂仪控系统的重要组成部分。本文介绍了AP1000功率量程中子注量率正变化率高紧急停堆的基本原理,对该紧急停堆信号触发与停堆定值、时间常数、功率变化率的关系进行了分析,并以MATLAB软件为平台,基于弹棒事故和正常运行瞬态两种典型工况的瞬态过程数据,对AP1000功率量程中子注量率正变化率高紧急停堆定值和时间常数的设计进行了仿真验证。     

系统瞬态分析程序中子学模块点堆求解验证

系统瞬态分析程序是用于示范快堆设计的工具软件之一,由中国原子能科学研究院自主开发,中子学模块是此程序中用于计算反应堆功率的模块。为了确保软件计算的正确性,需要对其进行验证与确认(V&V),本文对中子学模块求解点堆计算功率的结果进行了验证,是整个程序V&V工作中的一个部分。结果显示,在不同的条件下,中子学模块计算的结果与多种数值方法符合较好,满足程序计算的需求。     

大面积堆载预压对高速路桥基的影响

采用ANSYS软件对深圳市填海区堆载和沿江高速路桥基进行了三维计算分析,分别研究了不同工况下堆载过程自身发生的最大位移、位置,以及不同厚度堆载对桥基竖向位移及水平位移的影响,为类似工程的设计、施工和研究积累了宝贵的经验。     

弹棒事故的ATWT分析

随着燃料组件燃耗加深,燃料组件慢慢发生变形,当变形达到一定程度的时候将有可能导致控制棒组件不能完全插入堆芯,从而使得未停堆预期瞬态(ATWT)发生的概率大大的增加。ATWT的发生将会带来一系列严重的后果。进行了VVER-1000型核电站弹棒事故的ATWT分析,分析中考虑了保守的假设以及核电站实际运行经验的反馈。通过分析发现,当发生弹棒事故时,必须依靠停堆棒的引入反应性来满足反应堆的安全准则,仅仅依靠应急安注无法保证反应堆维持在安全状态下。     

模块式小型堆非能动堆腔注水冷却堆芯的严重事故分析

以模块式小型堆为研究对象,使用MELCOR程序建立了电厂模型。选取安注管线双端剪切断裂严重事故为保守事故序列,非能动堆腔注水系统(Passive Cavity Injection System,PCIS)投入后,分析堆芯热量通过吊篮和压力容器壁进入堆腔水的传热过程,并评价燃料棒结构状态。计算结果表明,堆芯支承板保持支撑燃料组件,堆芯大部分燃料组件包壳保持棒状结构状态,PCIS冷却压力容器外壁面带出堆芯热量实现堆芯冷却。     

子通道分析软件CORTH的验证与确认方法

子通道分析软件CORTH可以分析一系列子通道在稳态和瞬态工况下的单相流动和两相流动,能够在反应堆热工水力与安全分析领域发挥重要应用。工程设计软件计算结果的可信度很重要,因此需要对CORTH软件进行充分验证与确认。本文介绍了CORTH软件的验证与确认方法,给出了验证与确认的法规要求和关键步骤。核电厂堆芯出口温度分布验证计算结果表明CORTH软件的计算精度较高,能够满足工程设计与分析需求。     

Biological reactor resistance to inhibition

The phenomenon of complete substrate conversion within biological reactors in the presence of toxic compounds, called the Reactor Resistance to Inhibition (RRI), has been investigated. It was theoretically demonstrated that the RRI value, which means the highest concentration of inhibitor by which complete substrate conversion is possible, depends on liquid detention time. The excess detention time over that required for complete conversion, imply the existence of a “reserve” reaction potential. The value of this “reserve” can be reduced by inhibitor action with no influence on the observed substrate conversion rate. The influence of detention time on biological denitrification in Packed Bed Reactors in the presence of chromium Cr⁶⁺ was investigated. The RRI value for 1 h detention time was 1.5 mg l⁻¹ Cr⁶⁺. For 3 h detention time the RRI value was 22 mg l⁻¹ Cr⁶⁺. The relationship between the RRI value and detention time was linear.     

堆内构件安装技术

简要说明堆内构件的作用、组成,按安装主线详细描述了堆内构件的安装过程,分析并指出安装过程中的重点和难点,提出了应对措施和注意事项,以完善堆内构件安装技术,可为类似工程参考借鉴。     

Cultivation of Phanerochaete chrysosporium and production of lignin peroxidase in novel biofilm reactor systems: Hollow fiber reactor and silicone membrane reactor

The white rot fungus Phanerochaete chrysosporium and its extracellular enzyme lignin peroxidase are both known to catalyze the transformation and, in many cases, the degradation of several hazardous compounds and are, therefore, promising candidates for application in hazardous waste treatment. The application of P. chrysosporium in large-scale waste treatment and commercial production of lignin peroxidase has been impeded by the lack of bioreactor systems yielding consistent production of high levels of lignin peroxidase under long-term steady state conditions and controlled growth of the fungus. The use of innovative biofilm systems, which minimize intensive shear and provide for fungal growth as a biofilm, was investigated. The viability of the use of a hollow fiber reactor and a stirred tank reactor modified into a unique silicone membrane reactor for the cultivation of P. chrysosporium and production of high levels of lignin peroxidase was demonstrated. The membrane reactor utilizes silicone tubing as a growth support and for oxygenation. The silicone membrane reactor was operated using a repeated batch technique, consisting of alternating growth and production phases, to yield production of lignin peroxidase over a period of 5 weeks and appears promising for application as a hazardous waste treatment process.     

Sludge viability in a biological reactor

The volatile suspended solids (VSS) concentration cannot be used as a measure for the active biomass in a reactor which operates under a wide range of operating conditions since the viable organism content of the VSS is not constant. Using substrate saturation conditions the kinetic parameters maximum substrate removal rate ( ) and oxygen uptake rate (J)—both per mass of VSS—were determined in an experimental pulse fed batch biological reactor. It was found that and J both doubled during the experimental period (6 h). It was concluded that the increases in and J values were due to the increase in the sludge viability which are here defined as the percentage of VSS which is active biomass. Using the variations in and J values during each experiment, it was possible to calculate sludge viability. During a 6 h experimental period at substrate saturation level the sludge viability increased on average from 8.9 to 23.3%.In a loop type sewage conduits system operated as a plug flow reactor and enriched with biomass and air, it is possible to achieve high specific substrate removal rates when step feeding creates saturation conditions. This is further attenuated by a marked increase in the sludge viability.     

Hybrid reactor for priority pollutant-trichloroethylene removal

The present study was initiated to explore the potential of a hybrid biological reactor, combining trickling filter (TF) and activated sludge process (ASP), to treat wastewater containing trichloroethylene (TCE) at ambient temperature at different hydraulic retention time (HRT). The biofilm acclimation was achieved in 55-60 days with gradual increase in TCE concentration from 1 mg/l to 100 mg/l with a parallel increase in the concentration of substrate sodium acetate and other nutrients. COD and TCE concentration were taken as prime parameters for monitoring the growth of biofilm. During acclimation COD removal varied between 54.6-97.5% while TCE was removed 72.6-99.9%. HRT study was performed after acclimation. The removal efficiency increased with decreasing flow rate with maximum TCE removal (99.99%) at 6 l/d corresponding to an HRT of 28 h (TF 18 h + ASP 10 h). This was followed by a C:N:P ratio study. A ratio of 100:20:1 led to the sustenance of maximum TCE removal. Maximum TCE removal (99.99%) was observed at a substrate:cosubstrate ratio of 100:1. A pH of 7.4 +/- 0.2 was found to be optimum for degradation. Finally, volatilization losses were estimated to be 18.5%. A mass balance gave an efficiency of 81.51% for biological removal of TCE.     

一种新型电助光催化氧化反应器

设计了一种新型电助光催化氧化反应器--内外同心圆柱形反应器.考察了直流电压、电极布置方式、水力停留时间、反应器高度和半径等因素对反应器的影响,并分析了影响反应器设计的结构因子.研究表明,该反应器可有效降解苯甲酰胺.在本研究中,当反应器半径为3.5 cm,停留时间为120 min,直流电压为1.016 V时,苯甲酰胺的稳定去除率可达95%.     

Anaerobic dechlorination using a fluidized-bed GAC reactor

A simulated high-strength industrial wastewater containing acetate, phenol, and orthochlorophenol (2-CP) was treated using an anaerobic fluidized-bed granular activated carbon (GAC) reactor. Although carbon replacement was initiated to maintain the effluent quality from the reactor and to minimize the inhibitory effects of 2-CP, the latter phase of this study demonstrated that carbon replacement was not necessary. A large pulse input of organic feed was introduced to investigate the resilience of the reactor to severe and sudden increases in influent organic loading. With appropriate pH adjustment, the reactor stabilized within less than two days. A mathematical model was developed to investigate the interaction between the adsorption and biodegradation of compounds in the reactor during the large pulse input. The model confirmed that the GAC was instrumental in controlling the buildup of 2-CP in the reactor.     

A stochastic model of an ozonation reactor

Disinfection of some microorganisms is characterized by a lag-phase (a minimum required ozone exposure until disinfection occurs). This phenomenon is easy to model in laboratory batch reactors but not in continuous flow mixed reactors. This paper introduces a stochastic disinfection model where individual microorganisms are followed on their paths through full-scale reactors. Combining exponentially distributed transport processes with delayed exponential disinfection kinetics for large populations of microorganisms (up to 10,000 individuals) yields predictions which can be evaluated statistically. It could be shown that deterministic models work well for systems with good disinfection performance (more than 2 log units reduction of active microorganisms), for reactors with poor performance stochastic models have to be applied. It could be demonstrated for real reactors that Bacillus subtilis spores are poor surrogates for Cryptosporidium parvum oocysts. The differences between the two microorganisms are large for reactors that deviate significantly from plug-flow behaviour.     

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